Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F290/00—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups
  • C08F290/02—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups on to polymers modified by introduction of unsaturated end groups
  • C08F290/06—Polymers provided for in subclass C08G
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/24—Macromolecular compounds
  • C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B24/2641—Polyacrylates; Polymethacrylates
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/24—Macromolecular compounds
  • C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B24/2652—Nitrogen containing polymers, e.g. polyacrylamides, polyacrylonitriles
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
  • C04B24/24—Macromolecular compounds
  • C04B24/28—Macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • C04B24/32—Polyethers, e.g. alkylphenol polyglycolether
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
  • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
  • C08F265/10—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of amides or imides
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L51/003—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds

Definitions

• the present invention relates to a process for the preparation of water-soluble acrylic copolymers as well as to water-soluble acrylic copolymers and to their use as fluidizers or dispersants for hydraulic binders such as cements.
• plasticizers or dispersants in suspensions or pastes of hydraulic mineral binders is well known.
• the European patent application published under number 753488 relates to a cement dispersant obtained by polymerization in the presence of a chain transfer agent.
• a chain transfer agent an alcohol or a carboxylic acid containing a thiol group is used as chain transfer agent.
• the cement suspensions comprising such a dispersant are however not satisfactory as regards their rheological and economic properties.
• the European patent application published under the number 799 807 relates to a process for dispersing a cement composition, in which use is made of a polymer obtained by polymerization of a monomer component comprising a monomer of the alkoxypolyalkylene glycoimono ester type (meth ) acrylic produced by a meresterification reaction.
• the disadvantage of such a preparation is that it leads to the formation of secondary products of the functional ester type.
• di (meth) acrylics which causes crosslinking during polymerization and produces a crosslinked macromolecular polymer that does not perform as a dispersing agent for cement.
• European published under the number 976 769 proposes acrylic copolymers comprising the following repeating units:
• R a , R b , R c , Ri, Ru are equal or different and represent a hydrogen atom or a methyl group
• M + is a proton or a cation of an element of group IA or IIA, or an ammonium
• n is an integer between 0 and 2
• Ao is -COO- ( R ⁇ O) m -R z , where R ⁇ is a C 2 to C 4 saturated alkyl group, m is an integer between 7 and 50,?.
• Z is a hydrogen atom or a C_ to alkyl group C,; m is a hydrogen atom or the group COOH, COO " X " in which M + is as defined above or Ao as defined above; these copolymers optionally comprising a third type of repeating units in an amount between 0 and 20% relative to the total mass of the repeating patterns.
• copolymers which contain silanol groups in the terminal position, are obtained by copolymerization of the monomers in the presence of the following chain transfer agents:
• R IA is hydrogen or a C1 to C3 saturated alkyl
• R IB is a C1 to C3 alkyl
• NB is ⁇ n an integer worth 1 or
• NA is an integer worth 2 or 3
• R 0 is a linear or branched alkylene chain having from 1 to 2 carbon atoms; or a mixture of 'A with phosphorous or phosphoric mineral acids or their salts.
• copolymers have advantageous properties as far as the dispersion of the cement is concerned, however because the control of their molecular mass is obtained by means of the chain transfer agent, during their use, their structure is frozen, it does not change over time and does not change in function of the alkaline character of the medium.
• European patent application No. 747 374 relates to a hydrophilic contact lens formed by copolymerization of a polymerizable mixture comprising at least one hydrophilic monomer and further comprising at least one crosslinking agent; as an example of such a crosslinking agent is cited polyethylene glycol having, at its two terminal ends, acrylate or methacrylate groups.
• the subject of the invention is therefore the preparation of water-soluble acrylic copolymers which do not have the drawbacks which have just been mentioned.
• a first subject of the invention is therefore a process for the preparation of a water-soluble acrylic copolymer, comprising the following steps:
• Ri, R 2 , and R 3 are the same or different from each other and can be a hydrogen atom or a methyl group;
• Ao is a group -0 (RtO) m Rz or -NRp (RtO) m Rz, Rt being a saturated alkylene group having from 1 to 4 carbon atoms, Rz being a saturated alkyl group having from 1 to 6 carbon atoms and Rp being a hydrogen atom or a saturated alkyl group having from 1 to 8 carbon atoms;
• R x , R 2 , and R 3 are as defined above,
• a second subject of the invention relates to a water-soluble acrylic copolymer, capable of being obtained by a process comprising the following steps: (î) reaction of:
• Ao is a group -0 (RtC * ,, Rz or -NRp (RtO) m Rz, Rt being a saturated alkylene group having from 1 to 4 carbon atoms, m being -r an integer between 3 and 150, Rz being a saturated al yl group having from 1 to 6 carbon atoms and Rp being a hydrogen atom or a saturated alkyl group having from 1 to 8 carbon atoms; with - an excess of 'a derivative (1') of anhydride
• Ri, R 2, and R 3 are identical or different from each other and may be a hydrogen atom or a methyl group m ent; (11) optionally, partial or total neutralization, by neutral or basic hydrolysis, of the excess of the unreacted derivative (1 ′);
• step (m) copolymerization of the product obtained in step (n) with at least one monomer (2) of (meth) acrylic acid or of a derivative of this acid;
• step (n) if total neutralization is chosen in step (n), then a derivative (1) 'is chosen such that its neutralized form is different from the monomer (2).
• a third object of the invention relates to the use of a copolymer according to the invention or obtained by the process according to the invention as a fluidizer or dispersant in a hydraulic binder.
• a fourth object of the invention is a hydraulic binder composition comprising at least one copolymer according to the invention or obtained by the process according to the invention.
• a fifth object of the invention is an aqueous solution comprising at least one copolymer according to the invention or obtained by the process according to the invention.
• the invention provides the following advantages: - it provides acrylic copolymers with little or no crosslinking at all, which makes it possible to avoid the phenomena of gelation which make them unsuitable for many applications;
• the (meth) acrylic anhydride derivative (1') is acrylic anhydride or methacrylic anhydride which are prepared, for example, by reaction of meth) acrylic acid on acetic anhydride in the presence of a polymerization inhibitor.
• This reaction is described, in particular, in the French patent application published under the number 2,592,040.
• the procedure described in this document can be adapted by a person skilled in the art so that it allows the preparation of the derivative (1 ′) in which one and / or the other of the groups R 1 and R 3 is one (are) methyl group (s).
• the compound AoH can be either a compound of formula HO (RtO) m Rz, or a compound of formula HNRp (RtO) ra Rz.
• Ethoxy polyethylene glycol amme, ethoxy (polypropylene glycol ⁇ amme, ethoxy (polyethylene glycol) (polypropylene glycol) amme, ethoxy (polyethylene glycol) (polyoutylene glycol) amme, ethoxy (polypropylene glycol) ⁇ polybutylene glycol) ethoxy (polyethylene glycol) (polypropylene glycol) (polybutylene glycol) amme,
• R 4 [OC 2 H 3 (R 5 )] n OH, R 4 being a hydrophobic radical and R 5 a hydrogen atom or a methyl group.
• the reaction of the derivative l ') with the compound AoH is usually carried out at a temperature between 20 and 120 ° C, preferably between 30 and 100 ° C.
• the reaction time depends on the experimental conditions, such as the temperature and the quantities of catalyst used, but it is usually between 1 and 20 hours.
• the reagents are used according to a molar ratio of the derivative (1 ′) of (meth) acrylic anhydride to the compound AoH of between 0.6 and 3, preferably between 1.1 and 3.
• At least a polymerization unit such as hydroqumone or one of its derivatives (for example MeHQ), phenol derivatives such as BHT (2,6 diterbutyl hydroxytoluene) or phenotiaz e.
• the content of inhibitor (s) is generally between 100 and 5000 ppm. These inhibitors are generally used in the presence of an air stream in the reactor.
• the reaction is preferably carried out by introducing the reactants into the reactor at a temperature suitable for starting the reaction in the liquid phase. Then, the mixture is continued to stir at the reaction temperature, for the time necessary to complete the esterification or amidation.
• the mixture of monomers obtained is composed of an alkoxy ester monomer.
• Neutralization is then generally carried out by adding water or an alkaline solution to the reaction mixture at a temperature between 50 to 80 ° C for 5 to 8 hours.
• the level of unreacted derivative (1 ′) remains less than or equal to 20%, relative to the initial amount of derivative (1 ′) introduced. Neutralization is therefore preferable when the level of unreacted derivative (1 ′) is greater than 20%.
• the inventors have discovered that, surprisingly, the presence of an excess of the derivative () of (meth) acrylic anhydride advantageously leads to the protection of superplasticizers having good rheological and processing properties, due to their ability to gradually release linear active chains.
• a probaole explanation for this phenomenon is that complex copolymer networks are created when the derivative (1 ′) has not been neutralized or has been partially neutralized before the copolymerization step. These networks are then destroyed by the basicity of the hydraulic binder, which leads to the generation of new linear chains, which interact with the cement particles and thus modify their electrostatic and steric properties. The speed of generation of the linear chains produces an effect equivalent to the addition constant of linear polymers, in the hydraulic binder.
• the ratio between the free linear chains and the trapped linear chains can be adjusted by an appropriate choice of the amount of derivative (1 ′). In this way it is possible to obtain the desired activity of the copolymer.
• Partial neutralization is carried out as for the first embodiment, that is to say that water or an alkaline solution is added as indicated for the first preparation mode.
• water or an alkaline solution is added as indicated for the first preparation mode.
• the monomer (2) can correspond to the formula
• R a , R b and R c are the same or different from each other and can be a hydrogen atom or a methyl group;
• M ' is a hydrogen atom, a metal from group IA or IIA, ammonium or an organic amine group.
• monomers (2) there may be mentioned acrylic acid, methacrylic acid, their salts with alkali or alkaline earth metals, their ammonium salts and organic amines. Mixtures of these compounds can be used.
• acrylic acid or methacrylic acid is used as the monomer (2).
• Copolymerization is carried out with a weight ratio between the monomers (1) and (2) of between 5:95 and 98: 2, preferably between 50:50 and 98: 2.
• step (n) can be carried out in the presence of at least one other monomer (3) which is a monomer copolymerizable with the monomers (1) and (2).
• the mass proportion of this monomer (3) is generally between 0 and 20%, relative to the total mass of the monomers (1), (2) and (3).
• one or more monomers (3) chosen from:
• the copolymerization of the monomers (1), (2) and, where appropriate (3), is generally carried out in water, although short-chain alcohols, such as methanol, ethanol or l soprcpylic alcohol or other solvents such as ethyl ethyl ketone may also be suitable.
• short-chain alcohols such as methanol, ethanol or l soprcpylic alcohol or other solvents such as ethyl ethyl ketone may also be suitable.
• the process can be continuous, semi-continuous or discontinuous. It is also possible to carry out the copolymerization in the same reactor as that where the monomer (1) was prepared. This avoids changing the reactor, which constitutes an additional advantage of the invention. In this case, it may be desirable to adjust the mixture of monomers so that the molar ratios between the monomers are as desired.
• an appropriate radical reaction initiator is added to the mixture of monomers, in the form of a mass or in solution in water or in a solvent.
• an appropriate radical reaction initiator is preferably used, such as ammonium persulfate, sodium or potassium, hydrogen peroxide, with eu without activator such as that FeS0 4 , 7H 2 0, the sodium etabisulfite u ⁇ , ⁇ t ⁇ e purge the reactor with nitrogen.
• initiators which are soluble in the same medium, such as a hydroperoxide, ketone peroxides or percarbonates.
• a chain transfer agent can be used.
• thiol derivatives can be used.
• derivatives of the tr.iol type mention may be made of those cited on page 5, lines 41 to 48 of the aforementioned European patent application no. 799,807, in particular mercaptoethanol, thioglycerol, tmoglycolic acid, acid 2 - mercaptcpropionic, 3 -mercaptopropionic acid, thiomalic acid, octyl-thioglycolic acid, octyl-3-mercaptcpropionic acid, 2 -mercaptoethanesulfonic acid.
• these agents can be used alone or as a mixture.
• the thiol type chain transfer agents described in the aforementioned European patent application No. 976769 which are functionalizing chain transfer agents of formula HS-Ro-Si- (OR ⁇ a ), are used in the that the R is H or a saturated alkyl group, C -C 3, Ro is a linear or branched alkyl chain.
• These agents are used as such or as a mixture with H 3 P0 2 , H3PO3 or their salts. They are preferred because they introduce terminal polar groups (silanols), which improve the ability of the copolymer to attach firmly to the mineral particles.
• a particularly interesting chain transfer agent is ⁇ ercaptopropylt ⁇ méthoxys ⁇ lane.
• the reaction temperature may vary depending on the type of solvent used. In the case of an aqueous phase copolymerization, the temperatures are generally in the range of 50 to 120 ° C, preferably from 60 to 100 ° C.
• the reaction time is generally between 1 and 8 hours, preferably between 2 and 5 hours.
• the dry matter content of the aqueous polymer solution can vary between 23 and 70% by weight, it is preferably between 3: and 60%.
• a small amount of water can be poured into the reactor before the reactants are added.
• the reagents can be introduced simultaneously at constant flow rate, with stirring.
• the initiator can be added separately.
• the optional neutralization step can also take place at the end of the copolymerization reaction, during cooling.
• the reaction can be carried out batchwise, preferably in the reactor used for the preparation of the monomer (1), by mixing the monomers already present in the reactor with the other monomer (s), if the sounaite, before the start of the copolymerization.
• the copolymer is partially or totally neutralized during its formation, by simultaneous (but separate) introduction of an alkaline solution during the introduction of the mixture of -onomers into the reactor.
• the amount of alkaline solution introduced is calculated so that the neutralization is only partial and more preferably such that the amount of neutralized copolymer is between 40 to 70%.
• the copolymer partially or completely neutralizes the acrylic copolymer after the copolymerization step.
• the copolymer is then neutralized so that its pK is between 4 and 9.
• aqueous mixtures in the form of suspensions or pastes comprising the cement and copolymers according to the invention contain an amount of copolymer, generally between 0.03 and 2%, preferably between 0.05 and 1% by weight of reported copolymer. dry cement.
• copolymers according to the invention are added to the suspensions or cement pastes is carried out by introducing the copolymers as such or in the form of an aqueous solution comprising, by weight, more than 25% and preferably more than 30% of copolymer. Then mix until the mass becomes homogeneous.
• the volume of water is preferably reduced by the amount of water contained in the polymer solution, so as to maintain the water / desired cement.
• Another advantage provided by the invention is that, since aqueous solutions which may contain more than 50% of polymer can be produced in a reproducible and routine manner, these solutions can be sprayed using conventional equipment and according to conventional and inexpensive methods. .
• the cement composition can contain conventional additives such as air entrainers, anti-foaming agents, thickening agents, wetting agents, blowing agents, retarders or accelerators. taken, agents reducing shrinkage. It is also possible to introduce conventional dispersing agents for cement, such as dispersants based on sulfonated melamine or sulfonated naphthalene and formaldehyde based polymers, or lignin derivatives. Examples
• the concrete is kneaded for 30 seconds before each of the tests, then it is reintroduced into the rest of the cement suspension.
• the trapped air measurement is carried out on fresh concrete at 10 minutes according to NFP 18-353.
• the compression force is checked at 24 h, 7 days, 28 days according to the NFP 18-406 standard.
• the viscosity is determined at 30 revolutions per minute (pin 2) on a Broo ⁇ f ⁇ eld LVT2 viscometer at a temperature of 25 ° C or with a Rheology International viscometer, model R1: 2: M, pin 2 .
• the polymer In an aqueous solution of NH 4 OH, containing NaN 3 at a concentration of 0.02%, the polymer is dissolved at a concentration of ⁇ L ⁇ - (weight / volume) (40mg / 4 ml).
• the liquid phase ehromatography equipment consists of a Constomet ⁇ c '3200 pump, a Rheod e ® 7125 valve, a Diffential Refractometer R 401 * detector, a gel column? W 2000-4000 TSK S connected in series and thermostatically controlled at 40 ° C, and a Spectra Physics integrator " 1?
• the columns are calibrated with polyethylene glycols of variable molecular mass, 200 ⁇ l of sample solution are injected using as reference 1% dioxane (weight / volume) in water.
• the molecular weight of the polymer is determined according to the maximum of the elution peak.
• the amount of solution added to the cement is adjusted accordingly so that the polymer / cement ratio meets the given condition (0.175%). Differences in water content are compensated for by adjusting the total amount of water to meet the required water / cement ratio.
• Example 1 Preparation of a methacrylic ester of alkoxy polyalkylene glycol
• the equipment consists of a 2 liter glass reactor, equipped with a heating jacket connected to a thermostatic bath, equipped with a thermocouple, an agitator, an introduction pump, a dropping funnel and a condenser.
• Example 2 In the same reactor as in Example 1 previously heated to 80 ° C., 500 g (0.25 moles) of molten MPEG 2000 (methoxypolyethylene glycol of average molecular weight 2000) are introduced with stirring; 44.3 g (0.29 moles) of methacrylic anhydride; 0.6 g of BHT as stabilizer (3,5-d ⁇ -ter- butyl 4 hydroxytoluene); 5 g of t ⁇ ethylamme as catalyst.
• MPEG 2000 methoxypolyethylene glycol of average molecular weight 2000
• Reaction is carried out at 80 ° C for 7 hours, then a j ny 254 g of water and the mixture is hydrolysis of the anhydride by stirring the reaction mixture for 5 hours at 80 ° C. After cooling, an additional 245 g of water are added to reach a water concentration of approximately 50% of the ester.
• Example 2 In the same reactor as in Example 1 previously heated to 80 ° C., 500 g (0.5 mol) of molten Jeffamme® M 1000 (methoxy polyethylene glycol polypropylene glycol monoamme with an average molecular weight of 1000) are added with stirring. g / mol); 88.5 g (0.57 mole) of methacrylic anhydride; 0.6 g of BHT stabilizer (3,5-tert-butyl 4 hydroxytoluene).
• molten Jeffamme® M 1000 methoxy polyethylene glycol polypropylene glycol monoamme with an average molecular weight of 1000
• the reaction is carried out at 80 ° C for 4 hours, then 400 g of water are added, and the reaction is continued for a further 3 hours at 80 ° C.
• the final mixture is cooled to about 50% amide and used in the next copolymerization operation.
• the reaction is carried out at 80 ° C for 4 hours, then 385 g of water are added and the reaction is continued for a further 3 hours at 80 ° C.
• Example 5 Preparation of a methacrylic ester of alkoxy polyalkylene glycol containing non-hydrolyzed methacrylic anhydride
• MPEG 1000 methoxypolyethylene glycol of average molecular weight 1000 g / mole
• 108 g 0.7 mol
• methacrylic anhydride 0.6 g
• stabilizer BHT ⁇ 3,5-d tertbutyl 4 hydroxytoluene 5 g of triethylam e as catalyst.
• the reaction is carried out at 80 ° C for 6 hours; after cooling, 460 g of water are added to have a final content of approximately 50% of ester; the solution thus obtained is immediately used in the next copolymerization step.
• Example 6 Preparation of a methacrylic ester of alkoxypolyalkylene glycol containing non-hydrolyzed methacrylic anhydride
• aqueous mixture formed of 400 g of an aqueous solution prepared according to Example 1, 29.3 g of methacrylic acid; 4.4 g of Dynasylan® MTMO (3-mercaptopropyl-t ⁇ methoxysilane) as a functionalizing agent; and
• reaction is completed by adding, at once, 4 g of a 10% w / w solution of ammonium persulfate, and maintaining the temperature at about 80 ° C for about 1 hour.
• the polymer solution After cooling, the polymer solution has a dry matter content of 35.7% (viscosity 0.15 Pa. S at 100 revolutions per minute) and is almost completely neutralized with a 30% aqueous sodium hydroxide solution (final content dry matter 34%).
• the cement dispersant of the present invention has a weight average molecular weight of 22,000 and a maximum value of 14,000.
• the “mmislump” test as defined above is then carried out with the polymer solution. The results are reported below in Table 1.
• the preparation of the dispersant is carried out in a similar manner to that indicated for Example 7, but using 273 g of demineralized water as well as: - An aqueous mixture formed by 500 g of aqueous solution prepared according to Example 2, 16.8 g of methacrylic acid; 2.5 g of Dynasylan® MTMO (3-mercaptopropyl-trimethoxysilane as functionalizing agent; and
• reaction is completed by adding 4 g of a 10% w / w ammonium persulfate solution all at once and maintaining the temperature at 80-85 ° C for about 1 hour.
• the polymer solution After cooling, the polymer solution has a dry matter content of 35.7% and is almost completely neutralized using a 30% aqueous sodium hydroxide solution (dry matter content 35%).
• the cement dispersant of the present invention has a weight average molecular weight of 25,000 and a maximum value of 14,000.
• an aqueous mixture formed by 500 g of Bisomer 20 W, 28.9 g of methacrylic acid, 2.5 g of Dynasylan® MTMO (3-mercaptopropyl-tr ⁇ méthcxys ⁇ ane • as a functionalizing agent; and
• the reactor is charged with 390 g of demineralized water, then after heating to 80-85 ° C., the following is added:
• aqueous mixture consisting of 500 g of aqueous solution prepared according to Example 3; 32.7 g of methacrylic acid; 5.1 g of Dynasylan® MTMO (3-mercaptopropyl-trimethoxysilane) as a functionalizing agent; and
• the cement dispersant of the present invention has a weight average molecular weight of 22,000 with a maximum value of 11,000.
• the “minislump” test as defined above is then carried out with the polymer solution. The results are reported below in Table 1.
• the dispersant is prepared in a similar manner to that indicated for Example 7, but using the monomer mixture of Example 5. 277 g of demineralized water are introduced into the reactor, then after heating at 80 ° C. We add:
• reaction is completed by adding 4 g of a 10% (w / w) solution of ammonium persulfate all at once and maintaining the temperature at 80 ° C. for approximately 1 hour.
• the polymer solution After cooling, the polymer solution has a dry matter content of 35.7% and is then almost completely neutralized using an aqueous solution.
• the cement dispersant thus obtained has a weight average molecular weight of 30,000 and a maximum value of 17,000.
• Example 12 preparation of the dispersant according to the invention copolymerization
• the dispersant is prepared in a similar manner to that indicated for Example 7, but using the mixture of monomer of Example 6.
• 298 g of demineralized water are introduced into the reactor, then after heating to 80 ° C., the following are added: - A mixture formed by 5C0 g of aqueous solution prepared according to Example 6, 13.6 g of methacrylic acid; 2.5 g of Dynasylan® MTMO (-mercaptcpropyl-trimethoxysilane) as a functionalizing agent; and - 16 g of an aqueous solution (10% w / w) of ammonium persulfate ( H) 2 S 2 O ⁇ . After 3 hours, the reaction is terminated by adding 4.5 g of a 10% (w / w) solution of ammonium persulfate all at once and maintaining the temperature at 80 ° C.
• the cement dispersant of the present invention has a molecular weight by weight of 43,000 and a maximum value of 25,000.
• the preparation of the dispersant is carried out in a similar manner to that indicated for example 7, but using the mixture of monomer of example 6 as well as other monomers.
• the polymer solution After cooling, the polymer solution has a dry matter content of 36.0%. It is then neutralized with a 30% aqueous sodium hydroxide solution (final dry matter content: 35%).
• the cement dispersant according to the present invention has an average molecular weight of 118,000 and a peak value of 105,000, which shows that methacrylic anhydride resists hydrolysis and that there has been crosslinking. important.
• the dispersant is prepared in a similar manner to that indicated for Example 8, except that a 10 liter reactor is used and the molar ratio between the monomers is changed (2: 1 instead of 2 , 8: 1).
• reaction is completed by adding, in one go, 32 g of aqueous ammonium persulfate solution at 10% (m / m) and maintaining the temperature at 80 ° C for about one hour.
• the cement dispersant according to the present invention has a weight average molecular weight of 84,000 with peak values of 90,000 and 29,000.
• Table 2 establishes a comparison, obtained with “slump - •• measurements according to the test with an Abrams cone described above, between the dispersant of Example 14 and commercial products.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Ceramic Engineering (AREA)
• Engineering & Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Materials Engineering (AREA)
• Structural Engineering (AREA)
• Curing Cements, Concrete, And Artificial Stone (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Macromonomer-Based Addition Polymer (AREA)
• Graft Or Block Polymers (AREA)
• Adhesives Or Adhesive Processes (AREA)

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• 2000
  • 2000-03-31 FR FR0004142A patent/FR2807045B1/fr not_active Expired - Fee Related
• 2001
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  • 2001-03-27 ES ES01919577T patent/ES2217133T3/es not_active Expired - Lifetime
  • 2001-03-27 DK DK01919577T patent/DK1274663T3/da active
  • 2001-03-27 AT AT01919577T patent/ATE260225T1/de not_active IP Right Cessation
  • 2001-03-27 JP JP2001572433A patent/JP2003529641A/ja not_active Withdrawn
  • 2001-03-27 AU AU46650/01A patent/AU4665001A/en not_active Abandoned

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